Which is what makes the Oakland Raiders’ quest for a quarterback in the draft this May so fascinating. Despite all the film, the scouting reports and the interviews at the NFL Combine, pro teams seem just as likely to come up with a strikeout as a home run.

For weeks now, the top three quarterbacks available in the draft have been reported to be Teddy Bridgewater of Louisville, Johnny Manziel of Texas A&M and Blake Bortles of Central Florida.

But now, Fresno State quarterback Derek Carr has apparently leaped into the top three – meaning Manziel might be the one to drop on draft day.

And reports over the weekend indicate the Raiders are among those who prefer Carr.

In his latest mock draft Sunday, NFL writer Sam Farmer of the Los Angeles Times had the Jaguars taking Bridgewater at No. 3 and the Browns taking Bortles at No. 4, with the Raiders then selecting Carr – allowing Manziel to drop all the way to the Vikings at No. 8.

“The Raiders are known for their unconventional picks, so Manziel might seem like a natural fit for them,” wrote Farmer. “Word is, though, that they liked Carr more coming out of the combine.”

Daniel Jeremiah of NFL.com reported, too, that the Browns also are among several teams that prefer Carr over Manziel. And Chase Goodbread of NFL.com added that 17 NFL quarterback coaches polled at the combine rate Carr over Manziel as an NFL prospect. Before the combine, Carr was ranked among a group – that also includes Alabama’s A.J. McCarron – in a second tier of prospects.

Goodbread noted that there is “a faction of Manziel doubters” among the league’s coaches, and adds: “But more than half the league preferring Carr begs the question: How many prefer him over Bortles and Bridgewater, as well?”

The pressure on the Raiders to make the right pick is enormous. Make the correct call, and the Raiders are set for a decade. Make the wrong call, and the franchise again takes a big step backward. And all the while, the only certain way to know if you’ve got the right guy is to see him play in the NFL. It’s the kind of inexact science that could get GM Reggie McKenzie and head coach Dennis Allen ousted after this season, or in line for kudos.